Confounds and Artifacts
Encyclopedia
Although often used interchangeably, confounds and artifacts refer to two different kinds of threat to the validity of social psychological
research.
Within a given social psychological experiment, researchers are attempting to establish a relationship between a treatment (also known as an independent variable
or a predictor) and an outcome (also known as a dependent variable or a criterion). Usually, but not always, they are trying to prove that the treatment causes the outcome, that differential levels of the treatment lead to differential levels of the outcome.
. Construct validity refers to the degree to which a hypothesized psychological concept actually exists. A confound exists when the treatment influences the outcome, but not for the theoretical reason
proposed by the researchers. That is, the proposed construct (treatment) does not influence the outcome. Because confounds are intrinsic in the treatment (the construct of interest), they may be difficult to identify. Confounds may be related to the “reactivity” of the study (e.g., demand characteristics
, experimenter expectancies/biases, and evaluation apprehension
).
Suggestions for minimizing confounds include telling participants a believable and coherent cover story (to reduce demand characteristics or to attempt to keep them constant across conditions) and keeping researchers, research assistant
s, and others who have contact with participants “blind” to the experimental condition to which participants are assigned (to minimize experimenter expectancies/biases).
. Internal validity refers to whether the treatment actually causes the outcome. Artifacts are factors that covary with the treatment and the outcome. Thus, researchers cannot establish whether the outcome is the result of the treatment or the artifact. Campbell and Stanley identify several artifacts. The major threats to internal validity are history, maturation, testing, instrumentation, statistical regression
, selection, experimental mortality, and selection-history interactions.
One way to minimize the influence of artifacts is to use a pretest-posttest control group design. Within this design, “groups of people who are initially equivalent (at the pretest phase) are randomly assigned to receive the experimental treatment or a control condition and then assessed again after this differential experience (posttest phase)”. Thus, any effects of artifacts are (ideally) equally distributed in participants in both the treatment and control condition.
Social psychology
Social psychology is the scientific study of how people's thoughts, feelings, and behaviors are influenced by the actual, imagined, or implied presence of others. By this definition, scientific refers to the empirical method of investigation. The terms thoughts, feelings, and behaviors include all...
research.
Within a given social psychological experiment, researchers are attempting to establish a relationship between a treatment (also known as an independent variable
Independent variable
The terms "dependent variable" and "independent variable" are used in similar but subtly different ways in mathematics and statistics as part of the standard terminology in those subjects...
or a predictor) and an outcome (also known as a dependent variable or a criterion). Usually, but not always, they are trying to prove that the treatment causes the outcome, that differential levels of the treatment lead to differential levels of the outcome.
Confounds
Confounds are threats to construct validityConstruct validity
In science , construct validity refers to whether a scale measures or correlates with the theorized psychological scientific construct that it purports to measure. In other words, it is the extent to which what was to be measured was actually measured...
. Construct validity refers to the degree to which a hypothesized psychological concept actually exists. A confound exists when the treatment influences the outcome, but not for the theoretical reason
Speculative reason
Speculative reason or pure reason is theoretical thought , as opposed to practical thought...
proposed by the researchers. That is, the proposed construct (treatment) does not influence the outcome. Because confounds are intrinsic in the treatment (the construct of interest), they may be difficult to identify. Confounds may be related to the “reactivity” of the study (e.g., demand characteristics
Demand characteristics
In research, and particularly psychology, demand characteristics refers to an experimental artifact where participants form an interpretation of the experiment's purpose and unconsciously change their behavior accordingly. Pioneering research was conducted on demand characteristics by Martin Orne...
, experimenter expectancies/biases, and evaluation apprehension
Evaluation Apprehension
The evaluation apprehension theory was proposed by Nickolas B. Cottrell in 1972. He argued that we quickly learn that social rewards and punishments that we receive from other people are based on their evaluations of us. On this basis, our arousal may be modulated...
).
Suggestions for minimizing confounds include telling participants a believable and coherent cover story (to reduce demand characteristics or to attempt to keep them constant across conditions) and keeping researchers, research assistant
Research assistant
A research assistant is a researcher employed, often on a temporary contract, by a university or a research institute, for the purpose of assisting in academic research...
s, and others who have contact with participants “blind” to the experimental condition to which participants are assigned (to minimize experimenter expectancies/biases).
Artifacts
Artifacts, on the other hand, refer to threats to internal validityInternal validity
Internal validity is the validity of inferences in scientific studies, usually based on experiments as experimental validity.- Details :...
. Internal validity refers to whether the treatment actually causes the outcome. Artifacts are factors that covary with the treatment and the outcome. Thus, researchers cannot establish whether the outcome is the result of the treatment or the artifact. Campbell and Stanley identify several artifacts. The major threats to internal validity are history, maturation, testing, instrumentation, statistical regression
Regression analysis
In statistics, regression analysis includes many techniques for modeling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables...
, selection, experimental mortality, and selection-history interactions.
One way to minimize the influence of artifacts is to use a pretest-posttest control group design. Within this design, “groups of people who are initially equivalent (at the pretest phase) are randomly assigned to receive the experimental treatment or a control condition and then assessed again after this differential experience (posttest phase)”. Thus, any effects of artifacts are (ideally) equally distributed in participants in both the treatment and control condition.